Study on promotive effects of rice on seed germination of Potenderiaceae paddy weeds

阴道单色线虫车前草和红花车前草是严重危害稻田的水生杂草。近年来，在日本，通过直播和育苗移栽的方法增加了杂草的数量，这一问题变得更加严重。本研究通过测定水稻种子、秧苗、稻壳和稻草对杂草种子萌发的影响，得出了以下结果：在淹水条件下，水稻种子、稻草、稻壳和稻壳促进了阴道毛滴虫的萌发。无论供试品种，水稻种子、稻壳和稻草都能在黑暗中促进阴道毛霉种子的萌发。水稻种子、稻壳和稻草均能促进黄瓜种子的萌发和出苗，稻草、谷皮和稻壳中提取的水基残留物能在黑暗中刺激黄瓜种子的萌发。兴奋剂似乎已经取代了光。从稻草中分离出23种氨基酸和磷酸作为刺激剂的候选化合物。氨基酸和磷酸混合后，种子在黑暗中萌发。然而，该混合物不能诱导灭菌种子的萌发。这些结果表明，稻草产生的刺激物可能通过促进微生物的生长而诱导种子萌发，这些微生物在种子萌发中可能起着重要的作用。尿素和氨氮促进了阴道毛滴虫的萌发。尿素和水稻种子协同作用增加了幼苗的数量和生长阶段，类胡萝卜素生物合成抑制剂氟里酮和去甲氟拉松促进了阴道毛滴虫的出现。它们打破了种子休眠，防止了种子进入休眠状态，因此这些化合物可以有效地减少种子库中的种子数量。

Monochoria vaginalis var. plantaginea and Heteranthera limosa are very serious aquatic weeds in paddy fields. In recent years, they became a more serious problem in Japan where the number of the weeds was increased by the method of transplanting : direct-seeding and infant-seedling culture.This study was conducted to determine the effects of rice seeds, seedlings, hulls and straw on the germination of the weed seeds, and the following results were obtained.The emergence of M.vaginalis was promoted by the rice seeds, straw, hulls, and bran under submerged condition. The germination of the M.vaginalis seeds was stimulated in the dark by rice seeds, hulls and straw regardless of the cultivars tested. The germination and emergence of H.limosa were also promoted by rice seeds, hulls and straw.The aqueous residues extracted from rice straw, bran and hulls stimulated the seed germination of M.vaginalis in the dark. The stimulants seem to have replaced light. Amino acids (23 compounds) and phosphoric acid were isolated from rice straw as the candidate compounds for the stimulants. When the amino acids and phosphoric acid were mixed, they induced the seed germination in the dark. However, the mixture did not induce the germination of the sterilized seeds. These results suggest that stimulants produced by rice straw induce the seed germination possibly through enhancing the growth of microbes, which may play important roles in the seed germination.The emergence of M.vaginalis was promoted by urea and ammonium-nitrogen. Urea and rice seeds synergistically increased the number and growth stage of the seedlings.Fluridone and norflurazon, carotenoid biosynthesis inhibitors, promoted the emergence of M.vaginalis. They broke the seed dormancy and prevented the seeds from entering dormancy, thus these compounds can be usefull in decreasing the number of seeds in the seed bank.